Method and apparatus for sealing electrodes in envelopes of electron discharge tubes



Dec. 27, 1949 c. v. LITTON 2,492,162

METHOD AND APPARATUS FOR SEALING ELECTRODES IN ENVELQPES OF ELECTRONDISCHARGE TUBES Filed May 15, 1946 4 Sheets-Sheet 1 S L l2 INVENTORCHARLES V LITTON W Z' ATTO M Dec. 27, 1949 c. v. LITTON 2,492,162

METHOD AND APPARATUS FOR SEALING ELECTRODES IN ENVELOPES OF ELECTRONDISCHARGE TUBES Filed May 15, 1946 4 Sheets-Sheet 2 I'III: 9 ,u 40 25 42INVENTOR CHARLES v. LlTTON BY- z:

ATTORN EY Dec. 27, 1949 c. v. LITTON METHOD AND APPARATUS FOR SEA2,492,162 LING ELECTRODES IN ENVELOPES OF ELECTRON DISCHARGE TUBES 4Sheets-Sheet 3 Filed May 15, 1946 INVENTOR CHARLES V. LITTON ATTORNEYDec. 27, 1949 c, v, Lrr 2,492,162

METHOD AND APPARATUS FOR SEALING ELECTRODES -IN ENVELOPES 0F ELECTRONDISCHARGE TUBES Filed May 15, 1946 4 Sheets-Sheet 4 INVENTO CHARLES VLITT BYZ ATTORNEY Patented Dec. 27, 1949 mz'rnon AND APPARATUS FORSEALING amoraonas nv ENVELOPES F ELEC- raon' DISCHARGE TUBES 'Charles V.Litton, Redwood City, Calif., assignor to Federal Telephone and RadioCorporation, New York, N. Y., a corporation of Delaware Application May15, 1948, Serial No. 889,803 10 Claims. (Cl. 29-1795) 1 This inventionrelates to electrode supports and lead-in terminals for electrondischarge devices and to the method and apparatus for assembling .andattaching an electrode support to the wall of an electron dischargedevice so as to provide a connecting terminal for the electrode throughthe wall of said device.

One of the objects of the invention is to provide a rigid support for anelectrode of an electron discharge device which may be attached to thewall of the envelope thereof.

Another object of the invention is to provide an electrode support asdefined in the above paragraph which at the same time forms a terminalconnection for the electrode through the wall of the envelope of theelectron device.

Still another object of the invention is to provide a method and anapparatus for assembling and attaching an electrode support to the wallof an electron discharge device envelope.

Other objects of the invention and objects relating particularly to theconstruction and assembly of the various parts forming the electrodesupport and terminal will be apparent as the description of theinvention proceeds.

The invention is illustrated in the accompanying drawings in which:

Fig. 1 is a sectional side elevation of one end of an envelope of anelectron discharge device showing the electrode support assembly inposition just before attaching to the envelope wall;

Fig. 2 is a fragmentary sectional view of the electrode support assemblyattached to the wall of the envelope;

Fig. 3 is an elevational view partly in section of an apparatus forattaching the improved electrode support and terminal to the wall of theenvelope;

Figs. 4 and 5 are bottom plan and side elevational views, respectively,of the electrode support;

Fig. 6 is a perspective view of a portion of the assembling machineshowing the manner of holding the electrode support in position forincorporating into the discharge device;

Fig. 7 is a perspective view of the lathe chuck for supporting the neckof the envelope of the electron discharge device showing the movablebracket for holding the electrode support;

Fig. 8 is a sectional side elevation of the portion of an electrodesupport employed in accordance with my invention;

Fig. 9 is a sectional side elevation of a portion of the apparatus forforming an electrode support employed in accordance with my invention;

Fig. 10 is a sectional side elevation of a portion of the formingapparatus and the formed electrode support employed in accordance withmy invention;

Fig. 11 is a schematic diagram showing a modifled arrangement forreciprocating the assembled electrode support and terminal during theprocess of sealing it into the wall of the envelope.

Referring now to the several figures the invention has been disclosed inconnection with a high power vacuum tube the envelope of which has acylindrical glass portion I flared at one end, as at 2, for attachmentto another portion of the envelope (not shown) which may be the anode ofthe tube. The other end of the cylindrical portion I of the envelope isadapted to be attached to a base (not shown) which forms a support andprovides a lead-in for the cathode of the tube, the cathode extendingthrough the cylindrical portion I and into the anode portion of theenvelope. The arrangement of the anode and cathode of the tube form nopart of the present invention which is concerned chiefly with thesupport for the grid element.

The grid support 3, according to the present invention, comprises a ring4 of suitable metal provided with a right angular extension 5 by meansof which the support is attached to the terminal pin 6 which extendsfrom the wall of the envelope and forms a connecting terminal for thegrid of the tube. In order to give the support 3 sufficient strength'forits purpose and at the same time stamp it out of thin metal the ringportion 4 of the support is given a channel cross section and theangular extension 5 is provided with flanged edges, as indicated. Theseflanged edges extend along the sides of the extension 5 but terminatejust short of the rounded end of the extension. Reinforcing braces l arewelded between the extension 5 and the ring 4.

The grid (not shown) is supported within the anode and may be mountedupon support rods 8 which are welded or otherwise attached to the ringportion 4 of the grid support 3.

The extension 5 of the grid support 3 is'provided with a hole 9 which isadapted to fit over a cylindrical portion ID of a cup-shaped member IIwhich is adapted to be sealed into an opening I2 in the cylindrical wallI of the envelope in a manner to be later described. The hole I2 may beformed in any desired manner as by the known method of punching whilethe glass is hot and the edges thereof are upturned, as clearlyindicated in Fig. 1. The terminal pin 6 is shaped like a nail havingahead I3 which is of the proper diameter to fit into the cylindricalportion ill of the cup-shaped member II. The extension I the support 3is welded to the cup-shaped member II and the head I3 of the terminalpinis also welded within the cylindrical portion It so that the support3, the cup-shaped member II, and the'term'inal pin 6 form a rigidunitary member when properly welded together. The manner in which thisis done is described in detail in my copending application Ber. No.515,268, filed December 22, 1943, now Patent No. 2,452,582, grantedNovember 2, 1948. To provide a better understanding of my presentinvention, I shall briefly describe the method of forming the electrodesupport described in detail in the copending application.

First, it is desired to assemble the grid support 2 the cup-shapedmember II, and the terminal pin in a temporary manner preparatory to theflnal welding or fusing operations. This operation is preferablyperformed in a punch press indicated in Figs. 9 and 10, having astationary die member It over which the cup-shaped member II may bepositioned, the cup-shaped member being provided with a shoulder I5 toposition it upon the die member It in such a manner that the outer rimwill be spaced from the die member. The die member I4 is provided with acentral bore it into which the pin 5 may be inserted, and this bore isprovided with a piston Il urged upwardly by a spring I8 to keep the headof the terminal pin 5 against the cup-shaped member during theassembling operation.

Preferably, prior to the assembling of member II with extension 5 andpin 6, the cup-shaped member II is provided with a ring of glass I9which is fused to the tapered edge of the cupshaped member, as shown inFig. 8. This is for the purpose of more readily fusing the cupshapedmember II to the glass around the opening I2 in the cylindrical portionI of the envelope.

The terminal pin 5 is now inserted in the opening I6 of the die memberIt with the head I3 protruding from the top thereof. A disc 2I of silversolder or other brazing or soldering material is then placed on the topof the head I3, and the cup-shaped member I I is then placed over thedie member I3 with the head of the terminal pin extending into thecylindrical portion In of the cup-shaped member. A washer 22 of silversolder or other brazing or soldering material may then be placed overthe top of the cylindrical member III, the diameter of the hole in thewasher being sufiicient for the washer to fit easily over thecylindrical member. Then the electrode support 3 is applied by slippingthe extension 5 over the cylindrical member Ill.

The punch press is provided with a cooperating die member 23 which isthe same diameter or a little larger than the diameter of thecylindrical member ID, and this die I lember 23 is then broughtdownwardly in the direction of the arrow upon the top of the cylindricalmember I0. When pressure on the die member 23 is applied, thecylindrical member II) will start to deform, bulging outwardly at thetop over the extension 5 of the support 3 and bulging inwardly under thehead I3 of the terminal pin 6. It will be seen that this crimping actionholds the cup-shaped member, the terminal pin, and the electrode supportin physical gripping contact with each other and with the washer 22 anddisc 2 I of silver solder in position so that when heat is applied theseparts can be fused together.

The manner in which this unitary structure 4 comprising the terminalpin, the up-shaped member, and the electrode support held in physicalgripping contact with each other and with the washer 22 and disc 2| ofsilver solder in position as shown in Fig. 10 is such that when heat isapplied these parts can be fused together.

The manner in which this unitary structure comprising the terminal pin,the cup-shaped member, and the grid support (which may have the gridalready attached to it by means 0! the support rods 3) is fused into thewall 01' the envelope and the metal parts soldered or welded together ina single operation will now be described.

In order to position the parts properly for the assembling operation Iprovide a lathe chuck 24 for receiving the cylindrical end I of theglass envelope, a suitable contact members 25 being provided forgripping the glass without breaking it. The envelope I is positioned inthis lathe chuck with the hole I2 in the cylindrical wall at the lowerside. The lathe chuck 2| is rigidly supported upon an angle bracket 23which is in turn mounted upon a table 21, so that when the envelope I ispositioned in the lathe chuck, it is fixed with respect to the table anddoes not move in any direction or rotate.

It is desired to position the electrode support assembly within theenvelope for the fusing and welding operation in such a manner that itcan have a limited vertical movement with respect thereto for a purposeto be hereinafter described. To this end a plate 23 (Figs. 3, 6, and 7)is provided mounted on the back of the bracket 25 within guides 29 andill so that it can be moved vertically. A rod 3| is mounted upon theplate 28 by means of the screw 32, and this rod extends outwardlythrough an opening '33 in the bracket 26 and through the lathe chuck andthe tubular portion I or the envelope, terminating Just beyond theopening I2 in the envelope. At the end of this rod 3| is provided aplate 34 upon which the ring 4 of the electrode support 3 may betemporarily mounted. This mounting may be accomplished by means of aplurality of clips 35, pivotally mounted, one at each corner of theplate, which may be rotated by hand to have engagement with the ringportion I of the electrode support. When thus properly mounted on theplate 34 the electrode support assembly assumes the position shown inFigs. 1, 3, and 6 with the cup-shaped member II just above the inwardlyflared adges of the opening I2 in the envelope and with the terminal pin6 extending downwardly through the opening I2. I may prefer to place theelectrode support assembly in position before the envelope is placed inthe chuck, but the envelope may be positioned first, if desired. Thealignment of the hole I2 and the cup-shaped member II may be assured byaccurately positioning the hole in the cylindrical portion I of theenvelope and accurately positioning the envelope in the lathe chuck.

In order to raise and lower the grid support assembly the plate 28 isprovided with a rack 35 which is arranged to mesh with a gear wheel 31rotatably mounted upon a bracket 38 secured to the bracket 26 in anydesirable manner. Another gear wheel 39 is also rotatably mounted on asuitable stub shaft 40 on the bracket 33 and is arranged to mesh withthe gear 31. The end of the shaft 40 may be provided with a hand wheel Iwhich may be rotated by the operator to raise and a lower the electrodesupport assembly.

with a burner 48 at the and means to rotate it'andintocooperative'relation with through supported in the chuck.

A bearing 4! is provided for the pipe permitting it to rotate aboi tjtsown axis and at the same time permitting axial movement within thebearing. The pipe is rotated by means of a motor 4' supported on thetable upright which drives auxiliary shaft 41 journaledin a bearing 48also supported on the table upright. Thelghaft 41 carries a pulley 4!over which a belt ll thebeltalso assingaroundapulleyii securedto thepipe 42. Operation of the motor will continuously drive the pipe in onedirection.

The lower end of the pipe is provided with a rotary connection I!'tovwhich the gas is supplied by a rubber hose '3. The rotary connection8! permits the pipe 42 to rotate without disturbin the gas connection.

Means is provided for raising and loweringthe pipe by means of a footpedal I4 which is attached to the end of a lever 65 pivotally mounted ona bracket 5! attached to the floor under the table 21. The'lever II isconnected by means of a link 51 to the end of another lever I4 pivotallymounted to a bracket it secured to the floor. The

end of the lever 58 is bifurcated and straddles the pipe 42' beingpositioned thereon between two bearing members II. It will be seen thatwhen the foot pedal 54 is depressed the pipe 42 will be raised withoutinterfering with the supply of tion thereof owing to the flexibility ofthe belt II. A stop member I may be attached to the floor to limit themovement of the foot pedal and thus limit the movement of the burner 43with respect to the envelope i.

The burner 43 is cross sectioned in Fig. 1 and comprises a cylindricalmember with a conical upper face 0: which is internally threaded topermit screwing it on the end of the pipe 42. The burner 43 has acentral extension It provided with a bore 04 to receive the terminal pin6 when the burner is pushed up to a point near the cupshaped member Ii.Holes I in the burner head communicate with the interior of the pipe 42and the flames It are produced at the conical The burner 43 is ofsufficient diameter to fit into the cup-shaped member so that the flameswill be directed against the entire interior surface as well as againstthe edge of the hole I! in the envelope i.

For incorporating the electrode support'into the envelope the parts arefirst assembled as already described and the unitary structurecomprising the cup-shaped member Ii. the terminal pin 6 and theelectrode support 3, with the grid structure attached thereto by meansof the support rods I is mounted upon the plate 34 by means 6 shapedmember and the edge of the hole It. When the burner is raised so that itextendsinto the cup-shaped member, the pin I will pass into the bore 64in the burner. I

As soon as the glass at the edge of the hole I! and in the ring llattached to the edge of the cup-shaped member has' been raised to fusingtemperature and the metal parts have been heated so as to fuse thesolder disc 2! and washer 22 the hand-wheel 4i may be rotated so as tobring the assembly down towards the 'wall of the envelope so that theglass ring it touches the glass around the edge of the hole l2. As theglass fuses together, it is preferable to oscillate the handwheel 4iseveral times so as to raise and lower the electrode assembly through alimited distance and thereby puddle the glass to form a better fusingconnection. The foot pedal is then raised,

thus lowering the burner away from the connection.

A pair of marks 01 and .4 may be provided on the plate 28 and anglebracket 26, respectively,

' surface of which is pivoted a link ll which is in 7 gas thereto andwithout interfering with the rotaturn pivoted to an arm I4 attached tothe gear I have provided apparatus for attaching an electrode support tothe glass wall of a vacuum tube envelope which is simple and easilyconstructed. Also, the assembly of the support with the envelope may bequickly and easily accomplished without any partciular skill beingrequired.

Modifications may occur to those skilled in the art and the invention isnot intended to be limited except by the limitations of the appendedclaims.

What is claimed is:

1. The method of incorporating an electrode support having an innersupport member, an outer terminal member, and an intermediate member,into an electron discharge device having an envelope with at least aportion of the wall thereof of insulating material and said portionprovided with a hole therethrough having a size and shape conforming tothose of said intermediate member, which comprises first assembling thesaid members in their desired position with respect to each other,separated only by pieces of welding material, and temporarily securingsaid members in said position, then positioning the thus-secured memberswithin said envelope in approximately the desired position, with saidouter terminal member extending through the hole in said envelope walland the outer edges of said intermediate member adjacent the edges ofsaid hole, and subsequently heating said members and saidenvelope wallat the edges of said hole lesoassimultaneouslytoweldsaidmembersto- 2.The method according to claim 1 which ineludes the prior step or fusinga ring or insulatim material around the edge of the intermediate memberbefore positioning the temporarily secured members within the envelope,to facilitate fusing "-ldimember to the envelope wall.

3. Apparatus for mounting an electrode support assembly inan opening inthe side wall of an open-ended envelope or an electron discharge devicewhich comprises a chuck having a hollow portion adapted to receive andgrip a part of 'said envelope adjacent an open end thereof forsupporting the envelope in fixed position, an arm mounted forreciprocation within and relative to said hollow portion of said chuckand extending into said open end of the envelope, means to mount saidelectrode support assembly on the inner end of said arm with a portionof said assembly extending through said opening in the side wall andmeans movably mounted on said envelope supporting means andsupportingsaid arm within said hollow portion of said chuck to move said armtransversely with respect to said envelope supporting means so as tomove said electrode assembly with respect to said side wall.

4. Apparatus according to claim 3 in which there is further providedmeans simultaneously to heat said assembly and side wall adjacent to theopening therein.

5. Apparatus according to claim 3 in which the means to move the armholding the electrode support assembly comprises a member attached tosaid arm and slidably mounted with respect to said chuck, a rack securedto said slidable member, a pinion engageable with said rack, a crankstructure coupled to said pinion, and a motor coupled to said crankstructure, whereby said arm and the assembly mounted thereon is causedto reciprocate through a limited distance with respect to the wall ofthe envelope.

6. Apparatus for mounting an electrode support assembly in an opening inthe side wall of an open-ended envelope of an electron discharge devicecomprising a chuck adapted to receive and grip a part of saidenvelope'adjacent an open end thereof for holding the envelope in afixed position, said chuck having an opening through the center thereof,means for fixedly supporting said chuck, an arm extending through theopening in said chuck and into said open end of the envelope, meansto'mount said electrode support assembly on the end of said arm adjacentsaid opening in the side wall with a portion of said assembly extendingthrough said opening in the 'side wall and means movably mounted on saidchuck supporting means to move the said arm laterally with respect tosaid chuck so as to move said electrode support assembly with respect tosaid opening in the side wall of said envelope.

7. Apparatus for mounting an electrode support assembly in an opening inthe side wall of an open-ended envelope of an electron discharge devicecomprising a chuck adapted to receive and grip a part of said envelopeadjacent an open end thereof for holding the envelope in a fixedposition, said chuck having an opening through the center thereof, meansfor fixedly supporting said chuck, an arm extending through the openingin said chuck and into said open end of the envelope, means to mountsaid electrode support assembly on the end of said arm adjacent saidopening in the side wall, and means to move said arm laterally withrespect to said chuck so as to move said electrode support assembly withrespect to said opening in the side wall of said envelope comprising amember slidably mounted with respect to said chuck for movementsubstantially at right angles to the axis of said chuck and means tomove the said member to move the arm within the envelope laterally withrespect to said chuck.

8. Apparatus for mounting an electrode support assembly in an opening inthe wall of an open-ended envelope of an electron discharge device whichcomprises a chuck adapted to receive and grip a part of said envelopeadjacent an open end thereof for supporting said envelope, a base memberto'which said chuck is attached for supporting said chuck in fixedposition, said chuck and base member having axially aligned openingstherein, a plate slidably mounted upon said base member for limitedmovement in a direction at right angles to the axis of said chuck, anarm mounted on said plate and extending through the openings in saidchuck and base member and into the cylindrical portion of saidenvelope,-means at the inner end of said arm toretain said electrodesupport assembly thereon so thata portion of said assembly is positionedadJacent the opening in said side wall, a rack secured to said plate, apinion meshing with said rack, and means torotate said pinion so as tomove said arm and electrode support assembly within said envelopelaterally with respect to said chuck. I

9. Apparatus according to claim 6 in which there is further providedmeanssimultaneously to heat said assembly and side wall adjacent theopening therein.

10. The method according to claim 1 in which is provided the additionalsteps of moving the unitary structure of said members towards theenvelope wall to contact said outer edges of the intermediate memberwith thematerial of said wall adjacent said hole when the material ofsaid wall adjacent said hole is at fusing temperature, and moving saidunitary structure away from and towards the envelope wall while theouter edges of said intermediate member remain in contact with thematerial of said wall adjacent said hole, whereby there is insured amore perfect bonding between the intermediate member and envelope wall.

CHARLES V. LITI'ON.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Date

